Extracellular Volume Fraction (ECV) by MRI Calculator

Extracellular Volume Fraction (ECV) by MRI: Explanation and Clinical Context Extracellular Volume Fraction (ECV) quantifies the proportion of the myocardial tissue that is extracellular space, providing a non-invasive estimate of diffuse myocardial fibrosis and infiltration. The calculation uses pre- and post-contrast T1 values of myocardium and blood, corrected for the patient's hematocrit: ECV = (1 - Hct) × (ΔR1_myocardium / ΔR1_blood). Normal ECV values typically range from 20% to 30% in healthy myocardium, with higher values indicating increased interstitial fibrosis or infiltration (e.g., amyloidosis, hypertensive heart disease).

Clinically, ECV assessment helps in risk stratification, monitoring disease progression, and evaluating response to therapy.